A spoiler device for a vehicle is known. The known spoiler device for the vehicle includes an airflow control surface, or drag reduction surface that is formed continuously to a roof surface and the known spoiler device is provided at a roof end of the vehicle. Generally, there is a problem that air resistance, or drag of the vehicle increases by the generation of the vortex (trailing vortex) at the rear of the roof end caused by the airflow above a vehicle top surface flowing along the roof surface (upper surface flow). However, according to the known spoiler device (rear spoiler) provided on the vehicle, the generation of the vortex (trailing vortex) at the rear of the roof end can be restrained. Thus, aerodynamic characteristics can be enhanced.
Further, for example, JP2013-86571A (hereinafter referred to as Patent reference 1) discloses a structure in which plural protrusions that receive the wind caused by the running vehicle are provided near a rear windshield that wraps around opposite sides of the vehicle. The trailing vortex is generated, for example, by the airflow having relatively low flowing speed that flows along lateral surfaces of the vehicle at which protrusions, for example, side mirrors and door pillars are provided (lateral flow) is caught, or dragged to the back of the vehicle to be caught, or dragged to under the upper surface flow. According to the construction of Patent reference 1, the lateral flow is likely to be separated from a vehicle body by the protrusions. Thus, by restraining the air from being dragged to the back of the vehicle, the generation of the trailing vortex can be restrained.
Notwithstanding, for example, with a vehicle having a shape in which the incline of a rear surface (rear windshield) is steep because of design, the lateral flow to be caught, or dragged is increased. According to the vehicle constructed as described above, effects of the known device, for example, disclosed in Patent reference 1 is limited, and there remains room for improvement.
A need thus exists for a spoiler device for a vehicle which is not susceptible to the drawback mentioned above.